Insulator bushing and electrode for spark plugs



0. BEESCH May 20,1958

INSULATOR BUSHING AND ELECTRODE FOR SPARK PLUGS Filed July 17, 1953 @mmmmmmmmmmmmmmw United States Pate-r1 50 c INSULATOR BUSHING AND ELECTRODE FOR SPARK PLUGS Otto Beesch, Stuttgart-Zulfenhausen, Germany, assignor to Robert Bosch G. 111. b. H., Stuttgart, Germany Application July 17, 1953, Serial No. 368,576 Claims priority, application Germany July 26, 1952 7 Claims. (Cl. 313-136) The invention relates to a sparking plug in which an electrode pin consisting at least of two parts, the opposed ends of which abut each other and overlap each other with lateral bracing pressure is anchored in an insulator having a longitudinal channel In accordance with the present invention, the ends of the two parts overlap each other in axial side by side relationship and deflect each other by the side component of the axial pressure with which they touch each other and the longitudinal passage or channel in the region of such ends is wider than the greatest diameter of the overlapping ends, so that such ends are not supported on the wall of the passage or channel but are pressed together by the elasticity of the parts of the electrode pin.

The invention will be further described by way of example with reference to the examples of construction illustrated in the accompanying drawings in which:

Fig. 1 is a longitudinal section through a sparking plug insulator with parts of the electrode pin inserted therein. 1

Fig. 2 is a similar view as in Fig. 1 of a second embodiment of the invention.

Fig. 3 is a longitudinal section through a third embodi ment of the invention, and

Fig. 4 is a section on the line IV-IV of Fig. 3.

In Fig. 1, 1 is a ceramic sparking plug insulator which contains a stepped longitudinal bore 2. Into a narrow section of the longitudinal bore on the ignition side thereof, as illustrated at the bottom of the drawing, is cemented an electrode pin part 3 which is disposed with pressed out projections 4 on contacting a shoulder 5 in the longitudinal bore. The connecting side end 6 of this part of the electrode pin projects into the enlarged section of the longitudinal passage 2 and is enclosed for additional sealing by a pressed-1n ring 7 of packing powder over which glass powder paste is also inserted until over and above the end of the part of the electrode pin. Into this cushion of paste a second part 9 of the electrode pin is introduced from the connecting side of the plug having a normal connecting thread 1.0 on its outer end and on its inner end a flap 11 which is flattened off like the end of a tube bit and faces the part 3 of the electrode pin with a deep inclined surface 12.

facing the metal line. For more effective binding with the glass paste, the part 9 of the electrode pin is knurled at 9a on its peripheral surface connecting to the flap in longitudinal direction also. Upon penetrating the channel 2 the part 9 of the electrode pin displaces a part. of the glass powder paste into the gap between bolt and the channel in the insulator and then presses with its inclined surface 12 laterally against the upper end of the part 3 of the electrode pin producing a line contact between the parts of the electrode pin more or less longitudinally of the plug. At the same time this end is bent elastically and thereby produces, apart from good contact, also a lateral bracing force operating on both parts of the electrode. After penetrating the enlarged 5 heated that the glass powder paste fuses.

ice

section of the longitudinal bore 2 the part 9 of the elec trode pin is disposed with a collar 13 on the end surface of the insulator. After the introduction of the parts of the electrode pin the, insulator is dried and finally so After cooling, the parts of the electrode pin are firmly and tightly disposed in the insulator.

In the second example of construction as shown in Fig. 2 the longitudinal bore 2 of the insulator 1 is enlarged on the connecting side at 14. The part 3 of the electrode pin is introduced into the insulator and cemented in the same manner as in the first example of construction. The inner end 6 of the part 3 of the electrode pin projects only a short way into the section of the passage 2 intended for the reception of the part 9 of the electrode pin and this section is filled beyond its end 6 with glass powder paste after the insertion of the part 3. The part 9 of the electrode pin runs into the usual connecting thread 21 without a collar and a packing powder ring 15 is pressed inside the enlarged portion 14. The heat treatment and finishing of the connection part 9 of the electrode pin is the same as in the first example of construction. The passage 2 l is closed at the top by a'nut 16.

"In a third example of construction as shown in Figs. 3 and 4 the section of the longitudinal passage 2 intended to receive the part 9 of the electrode has a flattened cross section form, as shown in Fig. 4. The part 3 of the electrode is supported by its projection 4 through a disc 17 on the shoulder 5 in the insulator, is moreover cemented into the insulator, as in the first example of construction, and is sealed at the top of the shoulder with a packing powder ring 7. On the packing powder ring a suitable cement 18 is inserted into the channel 2 until above the slim, conically pointed inner end of the ignition side part of the electrode pin. The inserted part of the electrode pin 9 is likewise flattened in accordance with the section of the channel receiving it, so that these two parts cannot be twisted relative to each other. The end of the part 9 of the electrode pin facing the part 3 of the electrode pin is likewise pointed to form a slim cone. When this part in inserted into the passage 2, the conical points facing each other slide past each other, so that the two parts of the electrode pin are firmly braced against each other laterally inthe passage 2 thus ensuring the contacting of the two parts.

I claim:

1. A sparking plug comprising an insulator having a stepped longitudinal passage therethrough, an electrode pin extending axially through the passage and including a connecting end part and a separate ignition end part, each of said parts having an outer end externally of the passage and an inner end internally of the passage, the inner end of one of the parts being axially bevelled and the inner end of the other part contacting said bevelled end with the inner ends in axially overlapping relation, and means securing said parts in the passage under axial pressure so that said overlapping and contacting inner ends by virtue of their side by side contacting engagement deflect and brace each other by the side component of the axial pressure, said passage having a transverse width, in the region of which the inner ends overlap and said first and second mentioned portions, an electrode pin extending through said passage, a connecting end part and a separate ignition end part forming said electrode pin, a sideward projection on said ignition end part, each of said parts having one end externally of said passage and its other end abutting and overlapping the other end of the other part within the longitudinal passage, said ignition end part extending through said first mentioned portion of said passage and into said second mentioned portion with said sideward projection adjacent saidshoulder, means securing said ignition end part in said first mentioned portion of said passage, packing means surrounding part of said ignition end part within said second mentioned portion of said passage, the transverse width of said passage in the region in which said parts overlap and abut being wider than the greatest diameter of the overlapping and abutting ends of said parts, one of said other ends of said parts being bevelled thereby providing a lateral pressure between said other ends which touch each other side by side and deflect each other by the side component of the axial pressure with which the ends touch each other.

4. A sparking plug comprising an insulator having a stepped longitudinal passage therethrough, an electrode pin extending through said passage, a connecting end part and a separate ignition end part forming said electrode pin, longitudinal knurled ribs formed on part of said connecting end part, each of said parts having one end externally of said passage and its other end abutting and overlapping the other end of the other part within the longitudinal passage, the transverse width of said passage in the region in which said parts overlap and abut being wider than the greatest diameter of the overlapping and abutting ends of said parts, one 05 said other ends of said parts being bevelled thereby providing a lateral pressure between said other ends which touch each other side by side and deflect each other by the side component of the axial pressure with which the ends touch each other.

5. A sparking plug comprising an insulator having a stepped longitudinal passage therethrough, an electrode pin extending through said passage, a connecting end part and a separate ignition end part forming. said electrode pin, each of said parts having one end externally of said passage and its other end abutting and overlapping the otherend of the other part within the longitudinal passage, the transversewidth of said passage in the region in which said parts overlap and abut being wider than the greatest diameter of the overlapping and abutting ends of said parts, means restraining rotation of said connecting and part relatively to said insulator, one of said other ends of said parts being bevelled thereby providing a lateral pressure between said other ends which touch each other side by side and deflect each other by the side component of the axial pressure with which the ends touch each other.

6. A sparking plug comprising an insulator having a stepped longitudinal passage therethrough, said passage having a portion of smaller cross-sectional dimensions adjacent said ignition end, a portion of larger cross-sectional dimension adjoining said first mentioned portion and a shoulder connecting said first and second mentioned portions, an electrode pin extending through said passage, 2. connecting end part and a separate ignition end part forming said electrode pin, a sideward projection on said ignition end part, each of said parts having one end externally of said passage and its other end abutting and overlapping the other end of the other part within the longitudinal passage, said ignition end part extending through said first mentioned portion of said passage and into said second mentioned portion with said sideward projection adjacent said shoulder, means securing said ignition end part in said first mentioned portion of said passage, packing means surrounding part of said ignition end part within said second mentioned portion of said passage, the transverse width of second mentioned portion of said passage in the region in which said parts overlap and abut being Wider than the greatest diameter of the overlapping and abutting ends of said parts, the transverse dimension of said second mentioned portion in one direction being greater than the transverse dimension thereof in a direction at right angles thereto, part of said connecting end part having similarly a greater transverse dimension in one direction than its transverse dimension in a direction at right angles thereto whereby rotation of said connecting end part relatively to said insulator can be restrained, one of said other ends of said parts being bevelled thereby providing a lateral pressure between said other ends which touch each other side by side and deflect each other by the side component of the axial pressure with which the ends toucl each other.

7. A sparking plug comprising an insulator having a stepped longitudinal passage therethrough, said passage having a portion of smaller cross-sectional dimensions adjacent said ignition end, a portion of larger cross-sectional dimension adjoining said first mentioned portion and a shoulder connecting said first and second mentioned portions, an electrode pin extending through said passage, a connecting end part and a separate ignition end part forming said electrode pin, a sideward projection on said ignition end part, each of said parts having one end externally of said passage and its other end abutting and overlapping the other end of the other part within the longitudinal passage, said ignition end part extending through said first mentioned portion of said passage and into said second mentioned portion with said sideward projection adjacent said shoulder, means securing said ignition end part in said first mentioned portion of said passage, packing means surrounding part of said ignition end part within said second mentioned portion of said passage, the transverse width of second mentioned portion of said passage in the region in which said parts overlap and abut being wider than the greatest diameter of the overlapping and abutting ends of said parts, the transverse dimension of said second mentioned portion in one direction being greater than the transverse dimension thereof in a direction at right angles thereto, part of said connecting end part having similarly a greater transverse dimension in one direction than its transverse dimension in a direction at right angles thereto whereby rotation of said connecting end part relatively to said insulator can be restrained, said other end of said connecting end part and of said ignition end part being conical, thereby providing a lateral pressure and a line contact between said other ends'which touch each other side by side and deflect each other by the side component of the axial pressure with which the ends touch each other.

References Cited in the tile of this patent UNITED STATES PATENTS 1,169,203 Sprung Jan. 25, 1916 1,633,435 De Alcocer et al June 21, 1927 1,814,997 Wittner July 14, 1931 2,171,165 Rebezzana Aug. 29, 1939 2,235,325 Mohrle et al. Mar. 18, .1941 2,317,305 Schwartzwalder et al. Apr. 20, 1943 

